A court in Bangladesh has upheld the death sentences of a top Islamist militant and two of his supporters for a failed 2004 attack on a British diplomat.

The High Court dismissed the appeals of Mufti Abdul Hannan, who is chief of the banned group Harkatul Jihad al-Islami, and two of his followers. The three were convicted of attacking Anwar Choudhury, who at the time of the attack, was British high commissioner to Bangladesh.

Choudhury survived the grenade attack, which took place as he visited a Sufi shrine in the northeastern city of Sylhet. Three worshippers at the shrine were killed.

The three men were convicted in 2008 of murder and of planning the attack, and were sentenced to death. Two other militants were sentenced to life in prison.

Police said at the time that the attack was meant to "avenge the deaths of Muslims in Iraq and across the world by America and Britain."